Today's IT estimation techniques are simplistic in nature and are not well-suited for generating precise estimates for service-oriented projects. Service-oriented estimation requires the inclusion of additional factors in order to derive accurate project estimates. Specifically, the current estimation techniques and models do not take into account several variances (for example, culture, readiness, and organizational change, to name a few) which if not addressed have a significant impact on the reliability of the estimates. In fact, these variables in present estimation approaches must be discovered and accounted for in the form of new tasks without taking into account the impact to the estimation model if the task is not completed on time or satisfactorily. Such an approach often fails to account for the cultural adoption needed for the methods to be useable and, worse, the estimation model cannot account for the fact that the team has not adopted the methods which is an assumption in the estimation model.
Service-oriented architecture (SOA) requires a framework or estimation model which allows and recognizes both the specific tasks that must be completed as part of a project or program while taking into consideration both transformational goals often required as part of the project and maturity of the organization which will both implement and use the solution being estimated.
Drawbacks of known solutions include, among others, the following: primary focus on effort required for IT solution development/construction; focus only on development of IT components to fulfill the current set of requirements; a failure to take into account organizational maturity and skills maturity; factors that influence reduction in effort over time are not considered for estimation purposes; and the impact of re-factoring and reuse is not considered during estimation.